310 Notice of Ehrenberg's Memoir on Microscopic Life. 



southern end of South America to the polar extremity of North Amer- 

 ica, or through a range of more than 50° south to 60° north latitude. 



*Cocconei's placentula. *Gomphonema clavatum. 



* " Scutellum. " minutissimum. 



*Eunotia amphyoxys. *Pinnularia viridis. 



" biceps. *Stauroptera aspera. 



" Faba. *Spongiolithis acicularis. 

 *Fragillaria rhabdosoma. 



Those distinguished with a * are found agreeing in characters in 

 Central America and in Europe. 



8. Six species are distinguished from all the others by the peculiarity 

 of their forms, and are placed under the genera Climacosphenia, Go- 

 niothecium, Podosira, Rhizosolenia, Sphenosira and Terpsinoe. 



The music animalcule, Terpsinoe musica, which resembles a printed 

 sheet of music with twelve notes, standing by sixes in two rows, is re- 

 markably distinct from any European form. 



9. In America as in Europe, there occur not merely untraceable, 

 transient, momentary appearances of the minutest forms of life, but 

 also wide-spread fossil strata of their easily recognizable remains, which 

 form earthy and even rocky masses. 



10. The only American microscopic organisms which form earth 

 and rocks, are, as in Europe, the siliceous infusoria or the calcareous 

 Polythalamia. 



11. There occur in North America (Andover, Wrentham, Mass.) 

 fossil beds of siliceous earth, which are to a considerable extent com- 

 posed of loricated monads, (Trachelomonas,) and not formed as usual 

 merely of Bacillaria and Phytolitharia. Iron ochre occurs also in Mas- 

 sachusetts, which is very similar to the Gallionella deposits. 



12. Beds of minute fossil siliceous organisms have been observed of 

 the thickness of fifteen feet at Andover, and twenty eight feet at Rich- 

 mond. Similar beds occur by the Amazon in South America, and in 

 great extent from Virginia to Labrador. 



.13. The relations of the invisible calcareous Polythalamia are also 

 the same in America as in Europe ; indeed, the first short examination 

 alone has proved their gigantic development. They may be distinctly 

 recognized as forming the firm earth and the rocks of central North 

 America, as a cretaceous formation from New Jersey to the sources of 

 the Mississippi near the Rocky Mountains.* Even the Andes of the 



* Those who are not familiar with American geology should bear in mind that 

 the cretaceous formation only exists as a narrow belt along the Atlantic slope, 

 skirting the older formations which occupy the greater portion of the United 

 States, and that it is chiefly in the far west that it has the gigantic development 

 alluded to by Ehrenberg. 



